A slew drive is in essence a gearbox that is capable of withstanding axial and radial loads while being able to transmit torque to drive an external unit. There are many applications where a slew drive is utilized such, as solar trackers, wind turbines, lifts, and cranes, to name a few. They are generally constructed from a threaded shaft, commonly referred to as the worm gear and a geared wheel, commonly referred to as the worm wheel. The axes of rotation of the worm gear and worm wheel are, in general, perpendicular, although they can be at other orientations. A slew drive further includes bearings, seals, housings, a motor, and alternatively, a reducer assembly. The reducer assembly may comprise a series of planetary gear trains including planetary gears, sun gears, and carriers. The reducer assembly's input is coupled with the motor which operates at high speed and low torque. The reducer assembly's output is coupled with the worm gear which operates at a substantially lower speed but substantially higher torque.
A conventional slew drive generally includes a worm wheel, a worm gear, a reducer assembly, and a motor. The motor turns the reducer assembly and the reducer assembly rotates the worm gear which, in turn, rotates the worm wheel. The reducer assembly includes a coupling mechanism utilized to couple the reducer assembly to the worm gear. This coupling mechanism includes a carrier and a splined shaft. The carrier engages the splined shaft via its centrally located female splined bore. The carrier rotates the splined shaft which, in turn, rotates the worm gear via its own centrally located female splined bore.
In one configuration, the carrier and the splined shaft are fabricated as a one-piece mechanism which is utilized to couple the reducer assembly to the worm gear. This type of construction requires one or more seals in order to prevent the grease or oil, commonly used to lubricate the reducer assembly, from entering into the worm gear/worm wheel assembly.
An objective of the present design is to integrate the reducer assembly into the worm gear. Specifically, the slew drive includes a worm gear which further operates as a carrier, eliminating the need for a splined shaft and the seals, and shortening the overall length of the system.